A knout is whip made of multiple knotted cords, similar to the cat-o-nine-tails. I wonder what it says about us that we have so many synonyms for whip, which seem to be divided into two categories: everyday items that can be use to beat someone, such as cane, bat, belt, rod, ruler, and strap , and words which are primarily instruments of punishment: birch, crop, goad, scourge, switch, and of course whip (bull whip, horse whip, etc.).

The etymology of knout is from the Russian and is generally associated with the tsar. On the other hand, knot is thought to derive Germanic roots. However both derive from the Old Norse. Even though they share this common etymology, the arrived into the massive English lexicon by very different routes.